For obvious safety reasons, the important equipment of an automobile vehicle is provided with devices for detecting and signalling any anomalous operation.
The onboard generator, generally consisting of an alternator the phase voltages of which are rectified, is one such important equipment and all drivers know the location of the red “charging” indicator on the dashboard of their car.
The general use of vehicle onboard electronics, often substituted for electromechanical elements, provides ever more refined detection of malfunctions and circumstances conducive to breakdowns, for diagnostic or signalling purposes.
For example, the electronic voltage regulator described in U.S. Pat. No. 5,646,599 detects not only an anomalous battery charging voltage but also a fault affecting any of the alternator phase voltages and the duty cycle of the excitation current failing to conform to ranges of nominal values depending on the mode of operation of the alternator.
However, development of electronic systems also increases their complexity, which generates new requirements for detecting and signalling breakdowns.
Thus the electrical power supply unit described in U.S. Pat. No. 5,646,599 uses diode bridges as rectifiers. These components are considered reliable and a fault affecting any of them is detected only indirectly through monitoring the charging voltage.
On the other hand, if to improve efficiency diode bridges are replaced by synchronous rectifiers based on ad hoc control of metal oxide silicon field-effect transistors (MOSFETs), the problem arises of detecting and signalling malfunctions of the transistors and their control circuits.
The problem of detecting a fault can be easily solved at the component level by appropriate design of the component, but there remains the problem of signalling the fault, i.e. of making the driver aware of the anomaly that has been detected, which increases the complexity of the connectors and components and in a correlated way the cost. Moreover, the multiplicity of lamps or other indicators can be a drawback for drivers already swamped by the large amount of information shown on the dashboard of a vehicle.